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Dawn-dusk scale of dipolarization front in the Earth's magnetotail: multi-cases study
André, M.; Vaivads, A.; Deng, X. H. +10 more
We analyze three dipolarization front (DF) events to investigate their dawn-dusk scales in the Earth's magnetotail using the Cluster measurements in year 2007, when the spacecraft separation is about 1.8 Re (Re is the Earth's radius) and is appropriate for investigating the DF scale. Based on the Minimum Variance Analysis (MVA) and the general sha…
Fermi-LAT observations of the Sagittarius B complex
Aharonian, Felix; Yang, Rui-zhi; Jones, David I.
Aims: We use 5 years of Fermi-LAT data towards the Galactic-centre giant molecular cloud complex, Sagittarius B, to test questions of how well-mixed the Galactic component of cosmic rays are and what the level of the cosmic-ray sea in different parts of the Galaxy is.
Methods: We use dust-opacity maps from the Planck satellite to obtain …
Weather on Other Worlds. III. A Survey for T Dwarfs with High-amplitude Optical Variability
Metchev, Stanimir; Heinze, Aren N.; Kellogg, Kendra
We have monitored 12 T dwarfs with the Kitt Peak 2.1 m telescope using an F814W filter (0.7-0.95 µm) to place in context the remarkable 10%-20% variability exhibited by the nearby T dwarf Luhman 16B in this wavelength regime. The motivation was the poorly known red optical behavior of T dwarfs, which have been monitored almost exclusively at…
New Constraints on Cosmic Polarization Rotation from the ACTPol Cosmic Microwave Background B-mode Polarization Observation and the BICEP2 Constraint Update
di Serego Alighieri, Sperello; Xu, Lixin; Mei, Hsien-Hao +2 more
Recently, ACTPol measured the cosmic microwave background (CMB) B-mode and E-mode polarizations and obtained TE, EE, BB, TB, and EB power spectra in the multipole range 225-8725. In our previous paper (Paper I), we jointly analyzed the results of three experiments on the CMB B-mode polarization—SPTpol, POLARBEAR, and BICEP2—to include in the model…
Proton intensity spectra during the solar energetic particle events of May 17, 2012 and January 6, 2014
Dresing, N.; Heber, B.; Kühl, P. +4 more
Context. Ground-level enhancements (GLEs) are solar energetic particle events that show a significant intensity increase at energies that can be measured by neutron monitors. The most recent GLE-like events were recorded on May 17, 2012 and January 6, 2014. They were also measured by sophisticated instrumentation in space such as PAMELA and the El…
Transient Sulfate Aerosols as a Signature of Exoplanet Volcanism
Krissansen-Totton, Joshua; Sholes, Steven; Misra, Amit +1 more
Geological activity is thought to be important for the origin of life and for maintaining planetary habitability. We show that transient sulfate aerosols could be a signature of exoplanet volcanism, and therefore a geologically active world. A detection of transient aerosols, if linked to volcanism, could thus aid in habitability evaluations of th…
A Full Study on the Sun-Earth Connection of an Earth-directed CME Magnetic Flux Rope
Vemareddy, Panditi; Mishra, Wageesh
We present an investigation of an eruption event of a coronal mass ejection (CME) magnetic flux rope (MFR) from the source active region (AR) NOAA 11719 on 2013 April 11 utilizing observations from the Solar Dynamic Observatory, the Solar Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and the WIND spacecraft. The source…
Unveiling the nature of the γ-ray emitting active galactic nucleus PKS 0521-36
Ghisellini, G.; Pian, E.; Tosti, G. +11 more
PKS 0521-36 is an active galactic nucleus (AGN) with uncertain classification. We investigate the properties of this source from radio to γ-rays. The broad emission lines in the optical and ultraviolet bands and steep radio spectrum indicate a possible classification as an intermediate object between broad-line radio galaxies (BLRG) and steep spec…
Observational consistency and future predictions for a 3.5 keV ALP to photon line
Conlon, Joseph P.; Rummel, Markus; Alvarez, Pedro D. +2 more
Motivated by the possibility of explaining the 3.5 keV line through dark matter decaying to axion-like particles that subsequently convert to photons, we study ALP-photon conversion for sightlines passing within 50 pc of the galactic centre. Conversion depends on the galactic centre magnetic field which is highly uncertain. For fields at low or mi…
Distribution of sulphuric acid aerosols in the clouds and upper haze of Venus using Venus Express VAST and VeRa temperature profiles
Vandaele, Ann Carine; Tellmann, Silvia; Pätzold, Martin +8 more
Observations from Pioneer Venus and from SPICAV/SOIR aboard Venus Express (VEx) have shown the upper haze (UH) of Venus to be highly spatially and temporally variable, and populated by multiple particle size modes. Previous models of this system (e.g., Gao et al., 2014. Icarus 231, 83-98), using a typical temperature profile representative of the …